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Diffstat (limited to 'libdecnumber/dpd/decimal32.c')
| -rw-r--r-- | libdecnumber/dpd/decimal32.c | 491 |
1 files changed, 491 insertions, 0 deletions
diff --git a/libdecnumber/dpd/decimal32.c b/libdecnumber/dpd/decimal32.c new file mode 100644 index 0000000000..d8e3f59781 --- /dev/null +++ b/libdecnumber/dpd/decimal32.c @@ -0,0 +1,491 @@ +/* Decimal 32-bit format module for the decNumber C Library. + Copyright (C) 2005, 2007 Free Software Foundation, Inc. + Contributed by IBM Corporation. Author Mike Cowlishaw. + + This file is part of GCC. + + GCC is free software; you can redistribute it and/or modify it under + the terms of the GNU General Public License as published by the Free + Software Foundation; either version 2, or (at your option) any later + version. + + In addition to the permissions in the GNU General Public License, + the Free Software Foundation gives you unlimited permission to link + the compiled version of this file into combinations with other + programs, and to distribute those combinations without any + restriction coming from the use of this file. (The General Public + License restrictions do apply in other respects; for example, they + cover modification of the file, and distribution when not linked + into a combine executable.) + + GCC is distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. + + You should have received a copy of the GNU General Public License + along with GCC; see the file COPYING. If not, write to the Free + Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA + 02110-1301, USA. */ + +/* ------------------------------------------------------------------ */ +/* Decimal 32-bit format module */ +/* ------------------------------------------------------------------ */ +/* This module comprises the routines for decimal32 format numbers. */ +/* Conversions are supplied to and from decNumber and String. */ +/* */ +/* This is used when decNumber provides operations, either for all */ +/* operations or as a proxy between decNumber and decSingle. */ +/* */ +/* Error handling is the same as decNumber (qv.). */ +/* ------------------------------------------------------------------ */ +#include <string.h> /* [for memset/memcpy] */ +#include <stdio.h> /* [for printf] */ + +#include "dconfig.h" /* GCC definitions */ +#define DECNUMDIGITS 7 /* make decNumbers with space for 7 */ +#include "decNumber.h" /* base number library */ +#include "decNumberLocal.h" /* decNumber local types, etc. */ +#include "decimal32.h" /* our primary include */ + +/* Utility tables and routines [in decimal64.c] */ +extern const uInt COMBEXP[32], COMBMSD[32]; +extern const uShort DPD2BIN[1024]; +extern const uShort BIN2DPD[1000]; +extern const uByte BIN2CHAR[4001]; + +extern void decDigitsToDPD(const decNumber *, uInt *, Int); +extern void decDigitsFromDPD(decNumber *, const uInt *, Int); + +#if DECTRACE || DECCHECK +void decimal32Show(const decimal32 *); /* for debug */ +extern void decNumberShow(const decNumber *); /* .. */ +#endif + +/* Useful macro */ +/* Clear a structure (e.g., a decNumber) */ +#define DEC_clear(d) memset(d, 0, sizeof(*d)) + +/* ------------------------------------------------------------------ */ +/* decimal32FromNumber -- convert decNumber to decimal32 */ +/* */ +/* ds is the target decimal32 */ +/* dn is the source number (assumed valid) */ +/* set is the context, used only for reporting errors */ +/* */ +/* The set argument is used only for status reporting and for the */ +/* rounding mode (used if the coefficient is more than DECIMAL32_Pmax */ +/* digits or an overflow is detected). If the exponent is out of the */ +/* valid range then Overflow or Underflow will be raised. */ +/* After Underflow a subnormal result is possible. */ +/* */ +/* DEC_Clamped is set if the number has to be 'folded down' to fit, */ +/* by reducing its exponent and multiplying the coefficient by a */ +/* power of ten, or if the exponent on a zero had to be clamped. */ +/* ------------------------------------------------------------------ */ +decimal32 * decimal32FromNumber(decimal32 *d32, const decNumber *dn, + decContext *set) { + uInt status=0; /* status accumulator */ + Int ae; /* adjusted exponent */ + decNumber dw; /* work */ + decContext dc; /* .. */ + uInt *pu; /* .. */ + uInt comb, exp; /* .. */ + uInt targ=0; /* target 32-bit */ + + /* If the number has too many digits, or the exponent could be */ + /* out of range then reduce the number under the appropriate */ + /* constraints. This could push the number to Infinity or zero, */ + /* so this check and rounding must be done before generating the */ + /* decimal32] */ + ae=dn->exponent+dn->digits-1; /* [0 if special] */ + if (dn->digits>DECIMAL32_Pmax /* too many digits */ + || ae>DECIMAL32_Emax /* likely overflow */ + || ae<DECIMAL32_Emin) { /* likely underflow */ + decContextDefault(&dc, DEC_INIT_DECIMAL32); /* [no traps] */ + dc.round=set->round; /* use supplied rounding */ + decNumberPlus(&dw, dn, &dc); /* (round and check) */ + /* [this changes -0 to 0, so enforce the sign...] */ + dw.bits|=dn->bits&DECNEG; + status=dc.status; /* save status */ + dn=&dw; /* use the work number */ + } /* maybe out of range */ + + if (dn->bits&DECSPECIAL) { /* a special value */ + if (dn->bits&DECINF) targ=DECIMAL_Inf<<24; + else { /* sNaN or qNaN */ + if ((*dn->lsu!=0 || dn->digits>1) /* non-zero coefficient */ + && (dn->digits<DECIMAL32_Pmax)) { /* coefficient fits */ + decDigitsToDPD(dn, &targ, 0); + } + if (dn->bits&DECNAN) targ|=DECIMAL_NaN<<24; + else targ|=DECIMAL_sNaN<<24; + } /* a NaN */ + } /* special */ + + else { /* is finite */ + if (decNumberIsZero(dn)) { /* is a zero */ + /* set and clamp exponent */ + if (dn->exponent<-DECIMAL32_Bias) { + exp=0; /* low clamp */ + status|=DEC_Clamped; + } + else { + exp=dn->exponent+DECIMAL32_Bias; /* bias exponent */ + if (exp>DECIMAL32_Ehigh) { /* top clamp */ + exp=DECIMAL32_Ehigh; + status|=DEC_Clamped; + } + } + comb=(exp>>3) & 0x18; /* msd=0, exp top 2 bits .. */ + } + else { /* non-zero finite number */ + uInt msd; /* work */ + Int pad=0; /* coefficient pad digits */ + + /* the dn is known to fit, but it may need to be padded */ + exp=(uInt)(dn->exponent+DECIMAL32_Bias); /* bias exponent */ + if (exp>DECIMAL32_Ehigh) { /* fold-down case */ + pad=exp-DECIMAL32_Ehigh; + exp=DECIMAL32_Ehigh; /* [to maximum] */ + status|=DEC_Clamped; + } + + /* fastpath common case */ + if (DECDPUN==3 && pad==0) { + targ=BIN2DPD[dn->lsu[0]]; + if (dn->digits>3) targ|=(uInt)(BIN2DPD[dn->lsu[1]])<<10; + msd=(dn->digits==7 ? dn->lsu[2] : 0); + } + else { /* general case */ + decDigitsToDPD(dn, &targ, pad); + /* save and clear the top digit */ + msd=targ>>20; + targ&=0x000fffff; + } + + /* create the combination field */ + if (msd>=8) comb=0x18 | ((exp>>5) & 0x06) | (msd & 0x01); + else comb=((exp>>3) & 0x18) | msd; + } + targ|=comb<<26; /* add combination field .. */ + targ|=(exp&0x3f)<<20; /* .. and exponent continuation */ + } /* finite */ + + if (dn->bits&DECNEG) targ|=0x80000000; /* add sign bit */ + + /* now write to storage; this is endian */ + pu=(uInt *)d32->bytes; /* overlay */ + *pu=targ; /* directly store the int */ + + if (status!=0) decContextSetStatus(set, status); /* pass on status */ + /* decimal32Show(d32); */ + return d32; + } /* decimal32FromNumber */ + +/* ------------------------------------------------------------------ */ +/* decimal32ToNumber -- convert decimal32 to decNumber */ +/* d32 is the source decimal32 */ +/* dn is the target number, with appropriate space */ +/* No error is possible. */ +/* ------------------------------------------------------------------ */ +decNumber * decimal32ToNumber(const decimal32 *d32, decNumber *dn) { + uInt msd; /* coefficient MSD */ + uInt exp; /* exponent top two bits */ + uInt comb; /* combination field */ + uInt sour; /* source 32-bit */ + const uInt *pu; /* work */ + + /* load source from storage; this is endian */ + pu=(const uInt *)d32->bytes; /* overlay */ + sour=*pu; /* directly load the int */ + + comb=(sour>>26)&0x1f; /* combination field */ + + decNumberZero(dn); /* clean number */ + if (sour&0x80000000) dn->bits=DECNEG; /* set sign if negative */ + + msd=COMBMSD[comb]; /* decode the combination field */ + exp=COMBEXP[comb]; /* .. */ + + if (exp==3) { /* is a special */ + if (msd==0) { + dn->bits|=DECINF; + return dn; /* no coefficient needed */ + } + else if (sour&0x02000000) dn->bits|=DECSNAN; + else dn->bits|=DECNAN; + msd=0; /* no top digit */ + } + else { /* is a finite number */ + dn->exponent=(exp<<6)+((sour>>20)&0x3f)-DECIMAL32_Bias; /* unbiased */ + } + + /* get the coefficient */ + sour&=0x000fffff; /* clean coefficient continuation */ + if (msd) { /* non-zero msd */ + sour|=msd<<20; /* prefix to coefficient */ + decDigitsFromDPD(dn, &sour, 3); /* process 3 declets */ + return dn; + } + /* msd=0 */ + if (!sour) return dn; /* easy: coefficient is 0 */ + if (sour&0x000ffc00) /* need 2 declets? */ + decDigitsFromDPD(dn, &sour, 2); /* process 2 declets */ + else + decDigitsFromDPD(dn, &sour, 1); /* process 1 declet */ + return dn; + } /* decimal32ToNumber */ + +/* ------------------------------------------------------------------ */ +/* to-scientific-string -- conversion to numeric string */ +/* to-engineering-string -- conversion to numeric string */ +/* */ +/* decimal32ToString(d32, string); */ +/* decimal32ToEngString(d32, string); */ +/* */ +/* d32 is the decimal32 format number to convert */ +/* string is the string where the result will be laid out */ +/* */ +/* string must be at least 24 characters */ +/* */ +/* No error is possible, and no status can be set. */ +/* ------------------------------------------------------------------ */ +char * decimal32ToEngString(const decimal32 *d32, char *string){ + decNumber dn; /* work */ + decimal32ToNumber(d32, &dn); + decNumberToEngString(&dn, string); + return string; + } /* decimal32ToEngString */ + +char * decimal32ToString(const decimal32 *d32, char *string){ + uInt msd; /* coefficient MSD */ + Int exp; /* exponent top two bits or full */ + uInt comb; /* combination field */ + char *cstart; /* coefficient start */ + char *c; /* output pointer in string */ + const uInt *pu; /* work */ + const uByte *u; /* .. */ + char *s, *t; /* .. (source, target) */ + Int dpd; /* .. */ + Int pre, e; /* .. */ + uInt sour; /* source 32-bit */ + + /* load source from storage; this is endian */ + pu=(const uInt *)d32->bytes; /* overlay */ + sour=*pu; /* directly load the int */ + + c=string; /* where result will go */ + if (((Int)sour)<0) *c++='-'; /* handle sign */ + + comb=(sour>>26)&0x1f; /* combination field */ + msd=COMBMSD[comb]; /* decode the combination field */ + exp=COMBEXP[comb]; /* .. */ + + if (exp==3) { + if (msd==0) { /* infinity */ + strcpy(c, "Inf"); + strcpy(c+3, "inity"); + return string; /* easy */ + } + if (sour&0x02000000) *c++='s'; /* sNaN */ + strcpy(c, "NaN"); /* complete word */ + c+=3; /* step past */ + if ((sour&0x000fffff)==0) return string; /* zero payload */ + /* otherwise drop through to add integer; set correct exp */ + exp=0; msd=0; /* setup for following code */ + } + else exp=(exp<<6)+((sour>>20)&0x3f)-DECIMAL32_Bias; /* unbiased */ + + /* convert 7 digits of significand to characters */ + cstart=c; /* save start of coefficient */ + if (msd) *c++='0'+(char)msd; /* non-zero most significant digit */ + + /* Now decode the declets. After extracting each one, it is */ + /* decoded to binary and then to a 4-char sequence by table lookup; */ + /* the 4-chars are a 1-char length (significant digits, except 000 */ + /* has length 0). This allows us to left-align the first declet */ + /* with non-zero content, then remaining ones are full 3-char */ + /* length. We use fixed-length memcpys because variable-length */ + /* causes a subroutine call in GCC. (These are length 4 for speed */ + /* and are safe because the array has an extra terminator byte.) */ + #define dpd2char u=&BIN2CHAR[DPD2BIN[dpd]*4]; \ + if (c!=cstart) {memcpy(c, u+1, 4); c+=3;} \ + else if (*u) {memcpy(c, u+4-*u, 4); c+=*u;} + + dpd=(sour>>10)&0x3ff; /* declet 1 */ + dpd2char; + dpd=(sour)&0x3ff; /* declet 2 */ + dpd2char; + + if (c==cstart) *c++='0'; /* all zeros -- make 0 */ + + if (exp==0) { /* integer or NaN case -- easy */ + *c='\0'; /* terminate */ + return string; + } + + /* non-0 exponent */ + e=0; /* assume no E */ + pre=c-cstart+exp; + /* [here, pre-exp is the digits count (==1 for zero)] */ + if (exp>0 || pre<-5) { /* need exponential form */ + e=pre-1; /* calculate E value */ + pre=1; /* assume one digit before '.' */ + } /* exponential form */ + + /* modify the coefficient, adding 0s, '.', and E+nn as needed */ + s=c-1; /* source (LSD) */ + if (pre>0) { /* ddd.ddd (plain), perhaps with E */ + char *dotat=cstart+pre; + if (dotat<c) { /* if embedded dot needed... */ + t=c; /* target */ + for (; s>=dotat; s--, t--) *t=*s; /* open the gap; leave t at gap */ + *t='.'; /* insert the dot */ + c++; /* length increased by one */ + } + + /* finally add the E-part, if needed; it will never be 0, and has */ + /* a maximum length of 3 digits (E-101 case) */ + if (e!=0) { + *c++='E'; /* starts with E */ + *c++='+'; /* assume positive */ + if (e<0) { + *(c-1)='-'; /* oops, need '-' */ + e=-e; /* uInt, please */ + } + u=&BIN2CHAR[e*4]; /* -> length byte */ + memcpy(c, u+4-*u, 4); /* copy fixed 4 characters [is safe] */ + c+=*u; /* bump pointer appropriately */ + } + *c='\0'; /* add terminator */ + /*printf("res %s\n", string); */ + return string; + } /* pre>0 */ + + /* -5<=pre<=0: here for plain 0.ddd or 0.000ddd forms (can never have E) */ + t=c+1-pre; + *(t+1)='\0'; /* can add terminator now */ + for (; s>=cstart; s--, t--) *t=*s; /* shift whole coefficient right */ + c=cstart; + *c++='0'; /* always starts with 0. */ + *c++='.'; + for (; pre<0; pre++) *c++='0'; /* add any 0's after '.' */ + /*printf("res %s\n", string); */ + return string; + } /* decimal32ToString */ + +/* ------------------------------------------------------------------ */ +/* to-number -- conversion from numeric string */ +/* */ +/* decimal32FromString(result, string, set); */ +/* */ +/* result is the decimal32 format number which gets the result of */ +/* the conversion */ +/* *string is the character string which should contain a valid */ +/* number (which may be a special value) */ +/* set is the context */ +/* */ +/* The context is supplied to this routine is used for error handling */ +/* (setting of status and traps) and for the rounding mode, only. */ +/* If an error occurs, the result will be a valid decimal32 NaN. */ +/* ------------------------------------------------------------------ */ +decimal32 * decimal32FromString(decimal32 *result, const char *string, + decContext *set) { + decContext dc; /* work */ + decNumber dn; /* .. */ + + decContextDefault(&dc, DEC_INIT_DECIMAL32); /* no traps, please */ + dc.round=set->round; /* use supplied rounding */ + + decNumberFromString(&dn, string, &dc); /* will round if needed */ + decimal32FromNumber(result, &dn, &dc); + if (dc.status!=0) { /* something happened */ + decContextSetStatus(set, dc.status); /* .. pass it on */ + } + return result; + } /* decimal32FromString */ + +/* ------------------------------------------------------------------ */ +/* decimal32IsCanonical -- test whether encoding is canonical */ +/* d32 is the source decimal32 */ +/* returns 1 if the encoding of d32 is canonical, 0 otherwise */ +/* No error is possible. */ +/* ------------------------------------------------------------------ */ +uint32_t decimal32IsCanonical(const decimal32 *d32) { + decNumber dn; /* work */ + decimal32 canon; /* .. */ + decContext dc; /* .. */ + decContextDefault(&dc, DEC_INIT_DECIMAL32); + decimal32ToNumber(d32, &dn); + decimal32FromNumber(&canon, &dn, &dc);/* canon will now be canonical */ + return memcmp(d32, &canon, DECIMAL32_Bytes)==0; + } /* decimal32IsCanonical */ + +/* ------------------------------------------------------------------ */ +/* decimal32Canonical -- copy an encoding, ensuring it is canonical */ +/* d32 is the source decimal32 */ +/* result is the target (may be the same decimal32) */ +/* returns result */ +/* No error is possible. */ +/* ------------------------------------------------------------------ */ +decimal32 * decimal32Canonical(decimal32 *result, const decimal32 *d32) { + decNumber dn; /* work */ + decContext dc; /* .. */ + decContextDefault(&dc, DEC_INIT_DECIMAL32); + decimal32ToNumber(d32, &dn); + decimal32FromNumber(result, &dn, &dc);/* result will now be canonical */ + return result; + } /* decimal32Canonical */ + +#if DECTRACE || DECCHECK +/* Macros for accessing decimal32 fields. These assume the argument + is a reference (pointer) to the decimal32 structure, and the + decimal32 is in network byte order (big-endian) */ +/* Get sign */ +#define decimal32Sign(d) ((unsigned)(d)->bytes[0]>>7) + +/* Get combination field */ +#define decimal32Comb(d) (((d)->bytes[0] & 0x7c)>>2) + +/* Get exponent continuation [does not remove bias] */ +#define decimal32ExpCon(d) ((((d)->bytes[0] & 0x03)<<4) \ + | ((unsigned)(d)->bytes[1]>>4)) + +/* Set sign [this assumes sign previously 0] */ +#define decimal32SetSign(d, b) { \ + (d)->bytes[0]|=((unsigned)(b)<<7);} + +/* Set exponent continuation [does not apply bias] */ +/* This assumes range has been checked and exponent previously 0; */ +/* type of exponent must be unsigned */ +#define decimal32SetExpCon(d, e) { \ + (d)->bytes[0]|=(uint8_t)((e)>>4); \ + (d)->bytes[1]|=(uint8_t)(((e)&0x0F)<<4);} + +/* ------------------------------------------------------------------ */ +/* decimal32Show -- display a decimal32 in hexadecimal [debug aid] */ +/* d32 -- the number to show */ +/* ------------------------------------------------------------------ */ +/* Also shows sign/cob/expconfields extracted - valid bigendian only */ +void decimal32Show(const decimal32 *d32) { + char buf[DECIMAL32_Bytes*2+1]; + Int i, j=0; + + if (DECLITEND) { + for (i=0; i<DECIMAL32_Bytes; i++, j+=2) { + sprintf(&buf[j], "%02x", d32->bytes[3-i]); + } + printf(" D32> %s [S:%d Cb:%02x Ec:%02x] LittleEndian\n", buf, + d32->bytes[3]>>7, (d32->bytes[3]>>2)&0x1f, + ((d32->bytes[3]&0x3)<<4)| (d32->bytes[2]>>4)); + } + else { + for (i=0; i<DECIMAL32_Bytes; i++, j+=2) { + sprintf(&buf[j], "%02x", d32->bytes[i]); + } + printf(" D32> %s [S:%d Cb:%02x Ec:%02x] BigEndian\n", buf, + decimal32Sign(d32), decimal32Comb(d32), decimal32ExpCon(d32)); + } + } /* decimal32Show */ +#endif |